Fan geometry mixing laser

ABSTRACT

A mixing laser is fed by a plurality of glass discharge tubes arranged in a fan configuration each tube being fed by a helium source and a nitrogen source. The nitrogen source is electrically excited by a DC power supply and sent to a vacuum mixing chamber where the gases are mixed with cold carbon dioxide through bleed bars.

I United States Patent 1 1 1111 3,725,816 Mansell 1 51 Apr. 3, 1973 [54]FAN GEOMETRY MIXING LASER 3,577,096 5/1971 Bridges 331 945 1 1 Inventor:Dennis Manse", Paws Verde, 123???? 211333 Z JZifT??.II.... 11333113312Calif- 3,681,710 8/1972 Lary e161. ..331 94.5 [73] Assignee: The UnitedStates of America as represented by the Secretary of the 5 s g g g z '5;Air Force tt0rney arry er er r. e a.

[22] Filed: Apr. 28, 1972 [57] ABSTRACT [21] Appl. No.: 248,420 A mixinglaser is fed by a blurality of glass discharge tubes arranged in a fanconfiguration each tube being fed by a helium source and a nitrogensource. The [52] US. Cl ..331/94.5, 330/43 nitrogen Source iselectrically excited by a DC power [51] Ilit. pp y and Sent to a vacuumi g chamber where [58] Fleld of Search ..331/94.5; 3330/43 the gases aremixed with cold carbon dioxide through bleed bars. [56] References Cited4 Claims, 2 Drawing Figures UNITED STATES PATENTS 3,571,747 3/1971Bronfin ..331/94.5

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13b self-- 1, l l I I I 1711 3 -17 II I! FAN GEOMETRY MIXING LASERBACKGROUND OF THE INVENTION This invention relates to lasers, and moreparticularly to fan geometry mixing lasers.

In the past there has been the problem of constructing lasers with highpower outputs. This problem could be approached by increasing the lasersdimension. However, using this technique causes an increase in heat thatcould damage the optical components.

The invention solves the problem of scaling carbon dioxide mixing lasersto high powers and still keeping the length within reasonable bounds. Italso allows the use of larger diameter optics which has been a problemflux density and corresponding heating problems.

SUMMARY OF THE INVENTION Nitrogen gas is electrically excited in fiveglass discharge tubes and allowed to flow and converge into a vacuumcavity designed to smooth the flow and increase the gas velocity. Coldcarbon dioxide is added by means of vertical bleed bars and allowed tomix with the excited nitrogen. A 3 inches X 3 inches X 4 inches volumeof excited carbon dioxide is produced, and this volume is the heart ofthe laser system.

This laser produces a large cross-sectional area gain region whichallows large diameter optics to be used. No limit is imposed on thenumber of discharge tubes, as sections can be jointed side to side forvery high powered devices. Careful injection of carbon dioxide producesa relatively square gain cross section rather than an oblong crosssection in similar devices.

It is an object of the invention to provide a novel and improved gaslaser.

It is therefore another object to provide a gas laser capable ofdelivering very high power.

It is still another object to provide a gas laser having a large crosssection area which allows large diameter optics to be used.

It is yet another object to provide a gas laser having a relativelysquare cross section rather than an oblong cross section.

These and other objects, features and advantages of the invention willbecome more apparent from the following description taken in connectionwith the illustrative embodiment in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is partially a side view pictorialand partially a block diagram of an embodiment of the invention; and

FIG. 2 is a top view of the pictorial portion of that shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1and 2, there is shown mixing laser assembly 11 in which are connecteddischarge tubes l3a-l3e that can be made of any electrically insulatingmaterial but preferably of glass, and in a preferred embodiment thedimensions would be 2 inches in diameter and 18 inches in length.Nitrogen gas from nitrogen source 15 is injected in tubes l3a-l3 byconduits 17a-17e. Helium gas from helium source 19 is injected intotubes l3a -l3e via conduits 2la-21. The nitrogen gas is electricallyexcited by connecting one terminal of DC power supply 23 to electricallyconducting flanges 25a-2Se and the other terminal is connected to thechassis of vacuum cavity 27 which is a common or ground terminal withrespect to flanges 25a-25e. A preferred power supply would be l0-20kilovolts at 500 milliamperes.

The gases are allowed to flow and converge into vacuum cavity 27. Thissmooths the flow and increases the gas velocity. Cold carbon dioxidefrom carbon dioxide source 29 is added by means of vertical bleed bars31a-31f and allowed to mix with the excited nitrogen gas. An amount ofexcited carbon dioxide is produced in a volume such as 3 inches X 3inches X 4 inches which is shown as 33. The preferred mixture of gasesis 2 N 1 C0 1 He and mixed in a pressure of 20-60 torr. This vacuum isobtained from vacuum pump 35 which is attached to chassis 27 by flange37 and is operated at at least 3,000 CFM.

What is claimed is:

1. A laser assembly comprising:

a. a plurality of discharge tubes each tube having 1. means forinjecting nitrogen gas into the tube, 2. means for electrically excitingthe nitrogen,

b. a mixer chamber fed by the plurality of discharge tubes; and

c. means for injecting carbon dioxide into the chamber creating excitedcarbon dioxide.

2. A laser assembly according to claim 1 wherein the mixing chamber isevacuated and the discharge tubes are made of glass.

3. A laser assembly according to claim 2 wherein the means for injectingcarbon dioxide comprises a plurality of bleed bars.

4. A laser assembly according to claim 3 where the means forelectrically exciting the nitrogen is a DC power supply the terminalsthereof being connected to each extreme of the discharge tubes.

1. A laser assembly comprising: a. a plurality of discharge tubes eachtube having
 1. means for injecting nitrogen gas into the tube,
 2. meansfor electrically exciting the nitrogen, b. a mixer chamber fed by theplurality of discharge tubes; and c. means for injecting carbon dioxideinto the chamber creating excited carbon dioxide.
 2. means forelectrically exciting the nitrogen, b. a mixer chamber fed by theplurality of discharge tubes; and c. means for injecting carbon dioxideinto the chamber creating excited carbon dioxide.
 2. A laser assemblyaccording to claim 1 wherein the mixing chamber is evacuated and thedischarge tubes are made of glass.
 3. A laser assembly according toclaim 2 wherein the means for injecting carbon dioxide comprises aplurality of bleed bars.
 4. A laser assembly according to claim 3 wherethe means for electrically exciting the nitrogen is a DC power supplythe terminals thereof being connected to each extreme of the dischargetubes.